Concrete block



FIG. 1 is a perspective view of the present concrete block;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof; and,

FIG. 5 is a right side elevation view thereof (the left side view being symmetrical). 

The ornamental design for a concrete block, as shown and described. 